Explaining the reasoning behind the delay, Patrick Soderlund, executive vice president of EA Studios, said in a post:

In these last few weeks before launch, Respawn is in the final stages of polishing the Xbox One and PC versions of the game. Bluepoint is doing the same with the Xbox 360 version. To give them the time they need to put the finishing touches on the current-gen version of the game, we are moving the Xbox 360 ship date to March 25 in North America and March 28 in Europe. The extra two weeks will ensure the full world of Xbox gamers has an awesome experience.

Our Take:As my colleague Matt Miller pointed out, if Respawn is likely crunching just to finish the game in time for the Xbox One date – which surely has priority – it only makes sense that it's going to take some extra time for Xbox 360 developer Bluepoint to deal with the assets Respawn gives them.

Hhhhhhh... When, oh when, will people stop referring to the 360 and PS3 as "current gen"? They're not. Sorry if you own one, and you don't like hearing it, but those are no longer current gen systems. They are last gen.